This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -4 |
| 2 | -6 |
| 3 | 15 |
| 4 | 23 |
| 5 | -56 |
| 6 | -86 |
| 7 | 209 |
| 8 | 321 |
| 9 | -780 |
| 10 | -1198 |
| 11 | 2911 |
| 12 | 4471 |
| 13 | -10864 |
| 14 | -16686 |
| 15 | 40545 |
| 16 | 62273 |
| 17 | -151316 |
| 18 | -232406 |
| 19 | 564719 |
| 20 | 867351 |
| 21 | -2107560 |
| 22 | -3236998 |
| 23 | 7865521 |
| 24 | 12080641 |
| 25 | -29354524 |
| 26 | -45085566 |
| 27 | 109552575 |
| 28 | 168261623 |
| 29 | -408855776 |